/* POSIX spinlock implementation. ia64 version. Copyright (C) 2000, 2003 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Jes Sorensen <jes@linuxcare.com> The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include <errno.h> #include <pthread.h> #include "internals.h" #include <ia64intrin.h> /* This implementation is inspired by the implementation used in the Linux kernel. */ int __pthread_spin_lock (pthread_spinlock_t *lock) { int *p = (int *) lock; while (__builtin_expect (__sync_val_compare_and_swap (p, 0, 1), 0)) { /* Spin without using the atomic instruction. */ do __asm__ __volatile__ ("" : : : "memory"); while (*p); } return 0; } weak_alias (__pthread_spin_lock, pthread_spin_lock) int __pthread_spin_trylock (pthread_spinlock_t *lock) { return __sync_val_compare_and_swap ((int *) lock, 0, 1) == 0 ? 0 : EBUSY; } weak_alias (__pthread_spin_trylock, pthread_spin_trylock) int __pthread_spin_unlock (pthread_spinlock_t *lock) { return *lock = 0; } weak_alias (__pthread_spin_unlock, pthread_spin_unlock) int __pthread_spin_init (pthread_spinlock_t *lock, int pshared) { /* We can ignore the `pshared' parameter. Since we are busy-waiting all processes which can access the memory location `lock' points to can use the spinlock. */ return *lock = 0; } weak_alias (__pthread_spin_init, pthread_spin_init) int __pthread_spin_destroy (pthread_spinlock_t *lock) { /* Nothing to do. */ return 0; } weak_alias (__pthread_spin_destroy, pthread_spin_destroy)